Has anyone tried this before - SDA CRS+10?

TennMan

I have a pair of the CRS+ and monitor 10Bs. After looking both of them over for awhile I started to wonder if anyone has tried installing the crossovers and drivers from the CRS+ into monitor 10 cabinets to see how they would sound? If it has already been done could someone please post a link so I can read about it. I did a search and didn't find anything.

If it hasn't been done before...
I know some would consider it to be making a Frankenpolk or something but there's a pretty good chance of coming up with a smaller version of a SDA 2B that would sound really good. People experiment with the electronics all the time and end up with better sounding speakers. Why not experiment with the cabinets?

I see no reason the MWs and tweeters from the CRS wouldn't fit in the monitor 10 cabinets. The CRS crossovers and drivers appear to be electrically the same as the 2Bs so they weren't designed for a certain size cabinet. They should be right at home in the monitor 10 cabinets. It would just be a matter of figuring out how to mount the crossovers in the monitor 10 cabinets. I don't think the monitor 10 PRs would need to be changed. They are probably designed/tuned specifically for the volume of the monitor 10 cabinets.

Don't get me wrong, I've fell in love with my CRS+ speakers but I like the bass of my 10s better. I think the difference in the bass probably comes from a difference in the volume of the cabinets. The easy solution is to buy a subwoofer but I like trying new things better than making purchases.

It think it would be cool to say I had a pair of SDA CRS+10Bs! Plus, if you took the monitor 10 parts and put them in the CRS cabinets you would have a matching set of rear speakers. I'm not ready to attempt this myself. It's just an idea that lead me to ask if it has been done before and if so what was the result.

heiney9

That would be a Franken-polk.

None of the driver positions are even close to replicate the SDA correctly. IMO, a waste of time. Even if it might work a little bit what are you hoping to gain? You already have CRS+'s what's wrong with them that you think turning Monitor 10's into SDA's will fix?

H9

heiney9

I have heard CRS+'s put out copious amounts of bass, you need to work on positioning and stands if you don't already have proper stands.

What are you running the CRS+'s with?

H9

heiney9

The PR and cabinet size are also tuned to the specific parameters of the MW driver's chosen by Polk for that application. Unless the CRS+ drivers have the same electrical chacteristics then that formula is out the window. Not to mention the dimensional driver doesn't produce a full signal like the drivers in the Monitor 10.

You will end up with nothing but a mismatched mess.

H9

heiney9

On the plus side, it's pretty much a direct swap for all the parts so you'd only be out the time you spend swapping parts.

H9

pitdogg2

padding the post count ...again Brock?:loneranger:

Toolfan66

I find it a great idea, and I would try it if I had a set of 10's to do so. who cares if its a franken polk your not really modding anything..

I say go for it for the shear fun of doing so...

heiney9

pitdogg2 wrote: »

padding the post count ...again Brock?:loneranger:

No, just can't seem to put a stream of thoughts together in one post............

I would say he has nothing to lose, I just don't see the point of doing it because it's not going to give the results (more bass) he expects and the SDA is going to be diminished. But there is no harm in spending the time to swap parts. He may even like the result even though it may not be a "true" SDA type speaker. The problem is what to do with the parted out CRS+'s if he likes what he hears. I hate to see perfectly good SDA's parted for no good reason. Believe or not they are a limited species.

Just my .02c + .02c + .02c

H9

nspindel

Just chiming in with an opinion here. I used to own a pair of CRS+'s. The only mod I ever did to them was to swap out the SL2000's for 194's. I then sold those speakers when I grabbed a pair of 2B's, and then sold the 2B's when I moved to 1C's. But I owned the CRS+'s from 1989 until 2005, so I've had 16 years of experience with them. The CRS+ is an incredible pair of speakers, undoubtedly the best bang for the buck in the SDA family (well, in terms of original retail prices). Don't let their size fool you.

About a year ago I grabbed another pair of CRS+'s from Sal that I plan on doing every mod under the sun to. My wife and I will be selling our house in a couple of years and downsizing substantially, so I will be going back to the CRS+'s as my main speakers, and the 1C's will become the property of some lucky Polkie in the NYC area. I plan on doing my CRS+'s up right - veneer, rings, dynamat, armacell, sonicaps, Tony's boards, TL-mod/198's, Cardas posts, Dreadnaught, the works. This is a speaker so worthy of the best treatment possible. They pack an incredible punch. Once I get them done, they will be my speakers for life.

If you're not over-the-moon thrilled with the CRS+'s, then it's got to be an issue with your setup, and I don't think building a Franken Polk is going to sort you out. Figure out how to get the CRS+ to sound optimal, and you'll be more than happy.

heiney9

nspindel wrote: »

If you're not over-the-moon thrilled with the CRS+'s, then it's got to be an issue with your setup, and I don't think building a Franken Polk is going to sort you out. Figure out how to get the CRS+ to sound optimal, and you'll be more than happy.

Exactly

H9

TennMan

This will give you some good reasons to add to your post count.

heiney9 wrote: »

None of the driver positions are even close to replicate the SDA correctly.

You may be correct. The spacing could eliminate the SDA effect. I don't know. It could very well turn a worthwhile project into a waste of time. I was hoping someone had tried this and could tell me for certain from experience.

heiney9 wrote: »

The PR and cabinet size are also tuned to the specific parameters of the MW driver's chosen by Polk for that application...

That couldn't be correct because according to the '87 schematic (P01320003), SDA-2B / CRS use the same drivers and crossovers yet they have very different PR and cabinet sizes.

heiney9 wrote: »

... He may even like the result even though it may not be a "true" SDA type speaker. The problem is what to do with the parted out CRS+'s if he likes what he hears. I hate to see perfectly good SDA's parted for no good reason. Believe or not they are a limited species.

You are correct. It would not be a true SDA type speaker and in that configuration. However, it might be a speaker that I, as well as others, might really enjoy listening to. A different sound is the reason people mod their speakers. If the only purpose of changing parts was to keep the speakers sounding the same exact way as they sounded from the factory the vendors that sell the high dollar parts would be out of business.

Be assured that I have no intentions of doing anything to either set of speakers that would alter them in any way that couldn't be completely reversed. I wouldn't want to damage even as much as one screw in the cabinet.

If I were to undertake this project, and liked the results, I would install the 10 parts in the CRS cabinets for safe keeping and hold on to both sets of speakers. Otherwise I may sell the 10s at some point. Even though I like both sets of speakers the CRS+ are my favorites. Parting out either set of speakers is not even a consideration.

heiney9

I still think it's a waste of time as you aren't going to "marry" the sounds of the two to make a better sounding speaker. Which you stated is your goal.

But, knock youself out and of course document it for posterity.

My point on the MW drivers is if the parameters of the CRS+ drivers and 10B drivers are far enough apart they WILL affect the output. Of course you have know way of knowing from an engineering POV why different MW drivers w/different parameters were used in different models.

H9

Mr. Bubbles

I have never heard a pair of CRS but would love to. Currently my favorite SDA are my 2A's. I know that has nothing to do with anything other than since my favorites are the smallest that i own i would love to hear the smallest ones made. From looking at the ratios of cabinet/passive/driver in all the models the 2's have the highest amount of passive surface area and cabinet volume per driver than any of the others. I would assume then that I would probably like the detail and sound of the CRS but would most likely still be drawn to the 2's because of the more extended bass.

Given all of that, i would say go for it and see what happens. since i don't know what drivers the OP has in either set of speakers 6510, 6511, 6503 or a combination thereof. i would swap all drivers from the CRS+'s along with the CRS+ crossover into the 10B cabinets to be sure the crossover driver match is correct. The cabinet layout is very similar to the 2's although the drivers are lower and closer to the passives and the tweet is layed on it's side as in the first generation 2's but centered as in the later versions. given the spacing of the stereo driver to the dimensional driver the SDA effect could work ok, but stands may be beneficial to raise the plane of the drivers. The tuning of the passive will be different and there is not much way to guess how it will end up but it will probably have a deeper extension than the CRS+'s maybe not as smooth, but again there is no way to tell at this point. Some of the 10B's used 6503's and some of the CRS+'s used 6503's so the passives could be tuned correctly for the drivers if that turns out to be what he has.

If it sucks, it's easy enough to remove some screws and put it all back like it was before.

TennMan

nspindel wrote: »

Just chiming in with an opinion here. I used to own a pair of CRS+'s. The only mod I ever did to them was to swap out the SL2000's for 194's. I then sold those speakers when I grabbed a pair of 2B's, and then sold the 2B's when I moved to 1C's. But I owned the CRS+'s from 1989 until 2005, so I've had 16 years of experience with them. The CRS+ is an incredible pair of speakers, undoubtedly the best bang for the buck in the SDA family (well, in terms of original retail prices). Don't let their size fool you.

About a year ago I grabbed another pair of CRS+'s from Sal that I plan on doing every mod under the sun to. My wife and I will be selling our house in a couple of years and downsizing substantially, so I will be going back to the CRS+'s as my main speakers, and the 1C's will become the property of some lucky Polkie in the NYC area. I plan on doing my CRS+'s up right - veneer, rings, dynamat, armacell, sonicaps, Tony's boards, TL-mod/198's, Cardas posts, Dreadnaught, the works. This is a speaker so worthy of the best treatment possible. They pack an incredible punch. Once I get them done, they will be my speakers for life.

If you're not over-the-moon thrilled with the CRS+'s, then it's got to be an issue with your setup, and I don't think building a Franken Polk is going to sort you out. Figure out how to get the CRS+ to sound optimal, and you'll be more than happy.

Well, I'm new to SDAs and haven't had the opportunity to listen to all the other models like you have. My CRSs are the only SDAs I have ever heard so I may not realize how well they sound compared to the others. One of the main reasons I searched for a pair of CRS+ instead of 2Bs, or larger, is because I'm retired and now have a limited amount of space for speakers. If I had the room I would probably have waited for a larger pair of SDAs. I wish I could do all the mods that you have plans for in your next pair of CRS but funding isn't available for that right now.

I am absolutely thrilled with my CRS+ speakers. I do have some setup issues but that is not what prompted me to post a question about the CRS+10s. I just like to think outside the box and say "what if" every now and then.

heiney9

Oliver, while that is a good deduction and probably more true than not, the x-overs and progress they made from the SDA 2A to the final SDA CRS+ is quite a bit so I'm not so sure you can assume that.

Either way a properly set-up and powered pair of CRS+'s sounds superb and not wanting for bass until you get into the sub-bass category.

H9

heiney9

One other thing you guys are forgetting is in the 10's both MW's essentially play the same signal, in the CRS+ the dimensional driver is not a full range driver so you are already at a disadvantage, you will probably have less bass response.

H9

TennMan

heiney9 wrote: »

One other thing you guys are forgetting is in the 10's both MW's essentially play the same signal, in the CRS+ the dimensional driver is not a full range driver so you are already at a disadvantage, you will probably have less bass response.

H9

Not to be argumentative but isn't that true of the 2Bs as well? I've not heard them but I'm sure they have superior bass to the CRS+ and probably the monitor 10s. The only reason I can account for that, since the crossovers and the drivers are the same in some instances, is the extra volume of the cabinet. That's what brought on this crazy idea of a monitor 10-CRS hybrid that would have larger cabinet size and maybe some SDA qualities.

My intention is just to have fun making reversible changes to the speakers and maybe learning something from it at the same time. I'm not trying to convince anyone to try this. Just was wondering if they had.

heiney9

Have fun and be sure to report your findings. Despite my comments, I am interested in seeing what actually happens.

Be careful not to strip out any of the wood when swapping drivers. That's always my fear when removing the drivers, etc multiple times.

H9

Mr. Bubbles

heiney9 wrote: »

Oliver, while that is a good deduction and probably more true than not, the x-overs and progress they made from the SDA 2A to the final SDA CRS+ is quite a bit so I'm not so sure you can assume that.

Either way a properly set-up and powered pair of CRS+'s sounds superb and not wanting for bass until you get into the sub-bass category.

H9

I am not assuming any particular outcome with the project, just comparing what information we do have on this to what we don't and making comments based on that. A lot could be assumed but since we also don't know specifically which drivers he has in either pair there is also a lot that cannot be assumed. My biggest point is that since it is only screws that need be removed and replaced to perform this "project" why not give it a try and he can always put everything back like original after he has listened to it to see if he likes it or not.

I also understand that there are a lot of HARDCORE Polk fans here that get touchy about changing anything from the original Polk designs or design intentions. That's why i now test my own theories and KEEP THEM TO MYSELF. Even when they turn out good to my ears and measure good on my equipment I don't share those things here anymore. It's simply too stressful. I think i am a little like the OP in that my passion is listening to what i like to listen to no matter if it is a Franken -whatever or an original design by any number of manufacturers. I don't think he is trying to make a better SDA but it rather seems to me that he would just like to see if the sound may improve from the CRS+ with his idea. I personally would love to hear the outcome. it may be good or it may very well suck but we'll never know until someone tries. It is also very subjective, just like so many here love the SDA 1's; I find them disappointing

I would love to hear a pair of the CRS+'s properly set up. I personally think I would enjoy them and would not want to try what the OP is suggesting, but I already have the 2A's, 1C's, and SRS's.

I can see everyone's point on this one, but ultimately the speakers belong to the OP and he can do what he wants.

Mr. Bubbles

heiney9 wrote: »

One other thing you guys are forgetting is in the 10's both MW's essentially play the same signal, in the CRS+ the dimensional driver is not a full range driver so you are already at a disadvantage, you will probably have less bass response.

H9

Agreed completely but the extension should be much better depending on the passive tuning.

Toolfan66

I still say do it!!!! Nothing wrong with thinking outside the box, and your not hurting anything, and most of all they are your speakers to do what you wish to do to them..

Mr. Bubbles

heiney9 wrote: »

Have fun and be sure to report your findings. Despite my comments, I am interested in seeing what actually happens.

Be careful not to strip out any of the wood when swapping drivers. That's always my fear when removing the drivers, etc multiple times.

H9

I agree here completely. One of the biggest things here is that you want to be able to put it all back if you don't like it. Be careful and enjoy, but let us know how it works out.

phocion

From a dimensional standpoint, the drivers on the monitor 10's have just as much space between them as a pair of SDA 1C's, which are generally well regarded.

My gut feeling is that much of what you gain in bass from cabinet volume will be lost to the SDA effect with the reduction of drivers. On the other hand, the front firing PR should make the bass more overt and slightly less placement sensitive. Many people find the 10's to be boomy, and eschew them for the 7's, so you might hit a sweet spot by reducing the thump and adding SDA

Since it harms nothing to make the switch and experiment, (no mods to chassis or x-over) I think you should try it and report back!

halo71

phocion wrote: »

Many people find the 10's to be boomy,

"Many people"......where did you read this? Thats news to me.

heiney9

It is true and because of the side by side MW's the soundstage is smeared compared to the 5's or 7's.

The 10 is a great performer, but is my least favorite compared to the 5 and 7 tonally. It's a little bloated and suffers from midrange smearing and lack of openess in the mids.

H9

TennMan

oliverbubbles may have given me the best advice of all when he said he keeps ideas like this to himself. I didn't realize this idea would generate controversy. After all, what I suggested is minor compared to what has been done in other Polk mods. It actually isn't a modification of any parts so "parts swap" might be a better term to use for what I had in mind.

At any rate, I'm still interested in this and hope to get more input about it. I appreciate everyone's comments so far, pro and con.

I have went from wondering if it has been done before to wondering if I should try it. Before I go in that direction I will have to investigate whether or not the crossovers from the CRS could be mounted in the 10s without problems. I'm sure there is a lot of info here, with photos, that will show me how any extra parts in the CRS speakers are mounted. I just need to take the time to find it. If anyone can point me in that direction it would be helpful.

audiocr381ve

Kewel dude! Try it!

halo71

TennMan, don't sweat it! There are some here that do not do DIY stuff. I don't really see anything in this thread to be all that negative about your idea. If you are like me, you have more time than money. Then try your idea and let us know the outcome. I think many things in this world would not be around if it weren't for people trying something new. I love seeing DIY builds and speaker mods myself.


Brock, while I have never really found my 10's to be bloated or boomy. I do see what you are saying on the midrage smearing. Hey, I just got an idea! Both Monitor 10 drivers output the same frequencies right? Anyone ever disconnected one of the MW's??

heiney9

TennMan wrote: »

oliverbubbles may have given me the best advice of all when he said he keeps ideas like this to himself. I didn't realize this idea would generate controversy. After all, what I suggested is minor compared to what has been done in other Polk mods. It actually isn't a modification of any parts so "parts swap" might be a better term to use for what I had in mind.

At any rate, I'm still interested in this and hope to get more input about it. I appreciate everyone's comments so far, pro and con.

I have went from wondering if it has been done before to wondering if I should try it. Before I go in that direction I will have to investigate whether or not the crossovers from the CRS could be mounted in the 10s without problems. I'm sure there is a lot of info here, with photos, that will show me how any extra parts in the CRS speakers are mounted. I just need to take the time to find it. If anyone can point me in that direction it would be helpful.

Dude, we are just discussing it with you. Did you really think you'd throw this out there and everyone would be like "cool, do it". It's a discussion and I don't think anyone has said anything nasty or attacking anyone personally, etc.....it's a discussion forum and you will get all kinds of discussion about anything you choose to lay out for discussion.

It's all good, do it and report back. Don't be one of those who starts this whole idea and then we never hear anything back about it :biggrin:

H9

heiney9

My only word of advice and this would be for anyone working on these older speakers, is take you time and be careful. Parts start to get brittle, magnets can shift and the piss poor particle board they used for wood is dried out and it's easy to damage the baffle or strip the screws. Just take your time and be careful and you should be fine.

H9

TennMan

I've never found my 10Bs to be bloated. I have mine on stands that I made and I keep them off the back wall about 6". The walls on the sides are about 3 feet away. The room you have them in probably makes a difference in whether or not they sound boomy or bloated.